Suspension SETUP, a 'how to' guide...

PB Forum :: Mechanics' Lounge
Suspension SETUP, a 'how to' guide...
Author Message
flag ibishreddin
Posted: Aug 25, 2018 at 8:08 Quote
Anyone have problems with their dpx2 wallowing in the fist 70% of stroke? There is very little midstroke support but ramps up hard at the end. Transition sentinel 30% sag, .6 spacer
flag freestyIAM
Posted: Aug 25, 2018 at 21:38 Quote
ibishreddin wrote:
Anyone have problems with their dpx2 wallowing in the fist 70% of stroke? There is very little midstroke support but ramps up hard at the end. Transition sentinel 30% sag, .6 spacer

Not first hand experience, but this kinematic analysis of the sentinel suggests it's perhaps overly linear for an overforked bike. Maybe try to create more progressivety by adding more volume reducers in the pos air chamber. Or run more pressyre, maybe to 25% sag, if it doesn't unbalance the ride.

http://linkagedesign.blogspot.com/2018/01/transition-sentinel-29-2018.html?m=1
flag gpgalanis
Posted: Aug 25, 2018 at 22:15 Quote
For better mid stroke support you should remove a spacer (or add a smaller one) and increase the pressure.
flag ibishreddin
Posted: Aug 26, 2018 at 10:32 Quote
Will give it a go. Thanks, all
flag gpgalanis
Posted: Aug 26, 2018 at 14:02 Quote
By the way the DPX2 on my Sentinel feels a bit different. I am 220 (100 kg) and I initially put 250 psi but I didn't like it that much. There was definitely good mid stroke but also a bit harsh feeling and too much ramp up so I dropped it down to 225 and it feels a bit better but still there is too much ramp up.

My plan in to experiment a bit more but I will most probably install a smaller spacer at the end.
flag ibishreddin
Posted: Aug 26, 2018 at 17:35 Quote
gpgalanis wrote:
By the way the DPX2 on my Sentinel feels a bit different. I am 220 (100 kg) and I initially put 250 psi but I didn't like it that much. There was definitely good mid stroke but also a bit harsh feeling and too much ramp up so I dropped it down to 225 and it feels a bit better but still there is too much ramp up.

My plan in to experiment a bit more but I will most probably install a smaller spacer at the end.

How much sag before and after the change?
flag gpgalanis
Posted: Aug 26, 2018 at 21:29 Quote
Before around 30%, after around 35% (maybe a bit more) but I am still experimenting.
flag ajax-ripper
Posted: Aug 27, 2018 at 11:36 Quote
Your issue of too much ramp up is likely caused by too many volume spacers.

Remember; P1V1 = P2V2. As you compress the rear shock the possitive chamber will lose volume meaning the pressure will increase. This increase in pressure causes the spring rate to increase, Adding a volume spacer will reduce the starting volume of the chamber and the final volume of the chamber causing the pressure gain to be more substantial resulting in even more spring rate then you would have at the same point..

Usually you use volume spacers so you can run more sag to increase small bump sensitivity while still maintaining enoigh ramp up to not hit bottom. If you remove spacers run a slightly higher pressure and less sag. If you way less then 160 lb you should be running VERY few volume spacers as your regular pressure will be low enough to allow for good small bump and you shouldn't need the addition support.

hopefully I wrote this well enough and it makes sense.
flag freestyIAM
Posted: Aug 27, 2018 at 15:05 Quote
ajax-ripper wrote:
Your issue of too much ramp up is likely caused by too many volume spacers.

Remember; P1V1 = P2V2. As you compress the rear shock the possitive chamber will lose volume meaning the pressure will increase. This increase in pressure causes the spring rate to increase, Adding a volume spacer will reduce the starting volume of the chamber and the final volume of the chamber causing the pressure gain to be more substantial resulting in even more spring rate then you would have at the same point..

Usually you use volume spacers so you can run more sag to increase small bump sensitivity while still maintaining enoigh ramp up to not hit bottom. If you remove spacers run a slightly higher pressure and less sag. If you way less then 160 lb you should be running VERY few volume spacers as your regular pressure will be low enough to allow for good small bump and you shouldn't need the addition support.

hopefully I wrote this well enough and it makes sense.

On rereading the actual post which mentions lack of midstroke support instead of just going off the kenimatic analysis I would like to reverse my recommendation. @ajax-ripper and the others have it right. Your best bet for added mistroke support is increasing Positive air chamber volume (remove spacers) OR increase negative air chamber volume. I believe all DPX2's come with EVOL air cans and am not aware of an after market can that will give you even more negative air chamber volume but if one exists, that would also be a good bet for improving midstroke support.
flag ibishreddin
Posted: Aug 28, 2018 at 10:15 Quote
freestyIAM wrote:
ajax-ripper wrote:
Your issue of too much ramp up is likely caused by too many volume spacers.

Remember; P1V1 = P2V2. As you compress the rear shock the possitive chamber will lose volume meaning the pressure will increase. This increase in pressure causes the spring rate to increase, Adding a volume spacer will reduce the starting volume of the chamber and the final volume of the chamber causing the pressure gain to be more substantial resulting in even more spring rate then you would have at the same point..

Usually you use volume spacers so you can run more sag to increase small bump sensitivity while still maintaining enoigh ramp up to not hit bottom. If you remove spacers run a slightly higher pressure and less sag. If you way less then 160 lb you should be running VERY few volume spacers as your regular pressure will be low enough to allow for good small bump and you shouldn't need the addition support.

hopefully I wrote this well enough and it makes sense.

On rereading the actual post which mentions lack of midstroke support instead of just going off the kenimatic analysis I would like to reverse my recommendation. @ajax-ripper and the others have it right. Your best bet for added mistroke support is increasing Positive air chamber volume (remove spacers) OR increase negative air chamber volume. I believe all DPX2's come with EVOL air cans and am not aware of an after market can that will give you even more negative air chamber volume but if one exists, that would also be a good bet for improving midstroke support.

Agree. That would be ideal. Does the float x2 have bigger neg volume?
flag brianl
Posted: Sep 6, 2018 at 18:55 Quote
Does anyone know of a shop in Canada that sells suspension damper shims/valves? (Calgary or even Alberta would be ideal)
Online shops in the USA sell either in lots of 10, or for $15 worth of shims charge an extra $30 for shipping to Canada.
Main sizes I'm looking for are 10mm ID x 21mm x 0.10, 0.15mm thicknesses.
For a Manitou Mattoc Expert compression damper. It's pretty good but still a bit harsh even with minimum LSC/HSC/HBO and 30psi.
flag goytay
Posted: Sep 6, 2018 at 21:24 Quote
brianl wrote:
Does anyone know of a shop in Canada that sells suspension damper shims/valves? (Calgary or even Alberta would be ideal)
Online shops in the USA sell either in lots of 10, or for $15 worth of shims charge an extra $30 for shipping to Canada.
Main sizes I'm looking for are 10mm ID x 21mm x 0.10, 0.15mm thicknesses.
For a Manitou Mattoc Expert compression damper. It's pretty good but still a bit harsh even with minimum LSC/HSC/HBO and 30psi.

Give to folks at Fluid Function a call INFO@FLUID-FUNCTION.COM
flag brianl
Posted: Sep 8, 2018 at 15:17 Quote
goytay wrote:
brianl wrote:
Does anyone know of a shop in Canada that sells suspension damper shims/valves? (Calgary or even Alberta would be ideal)
Online shops in the USA sell either in lots of 10, or for $15 worth of shims charge an extra $30 for shipping to Canada.
Main sizes I'm looking for are 10mm ID x 21mm x 0.10, 0.15mm thicknesses.
For a Manitou Mattoc Expert compression damper. It's pretty good but still a bit harsh even with minimum LSC/HSC/HBO and 30psi.

Give to folks at Fluid Function a call INFO@FLUID-FUNCTION.COM
I got a reply back that they don't have any 10mm ID shims, dang.
flag goytay
Posted: Sep 8, 2018 at 16:10 Quote
brianl wrote:
goytay wrote:
brianl wrote:
Does anyone know of a shop in Canada that sells suspension damper shims/valves? (Calgary or even Alberta would be ideal)
Online shops in the USA sell either in lots of 10, or for $15 worth of shims charge an extra $30 for shipping to Canada.
Main sizes I'm looking for are 10mm ID x 21mm x 0.10, 0.15mm thicknesses.
For a Manitou Mattoc Expert compression damper. It's pretty good but still a bit harsh even with minimum LSC/HSC/HBO and 30psi.

Give to folks at Fluid Function a call INFO@FLUID-FUNCTION.COM
I got a reply back that they don't have any 10mm ID shims, dang.

info@suspensionwerx.com ?
flag brianl
Posted: Sep 8, 2018 at 18:10 Quote
goytay wrote:
brianl wrote:
goytay wrote:


Give to folks at Fluid Function a call INFO@FLUID-FUNCTION.COM
I got a reply back that they don't have any 10mm ID shims, dang.

info@suspensionwerx.com ?
This afternoon I emailed Suspensionwerx and some other shops, hopefully one of them can help me.

 


Copyright © 2000 - 2024. Pinkbike.com. All rights reserved.
dv65 0.025487
Mobile Version of Website